Due to DE 41 37 143 A1, we are familiar with a multi-step synchronized countershaft, in which two gears each are assigned to one of several gearshift packages. These gearshift packages generally consist of sliding collars which can be moved axially, but are torsion-resistantly arranged on a gearbox shaft which, in joint action with synchronic rings that are located close to these sliding collars on the shaft, brake and accelerate loose gear wheels, and can connect rotation-resistantly with this gearbox shaft.
In this transmission, the two gears (1st gear and 3rd gear or 2nd and 4th gear), which are allocated to a gearshift package, do not follow each other. This gear design has the advantage that it creates a gearshift system, which allows for an overlapping shift actuation and thus reduces the amount of time it takes to shift gears. A disadvantage is, however, that such a gear with a shifting device with H-gear shifting gate is difficult to shift, because normally only successive gears are shifted in the same gearshift path with an H-gear shifting gate.
Furthermore, due to EP 10 34 384 B1, one is familiar with a twelve gear gearbox for utility vehicles. In this gearbox, a pre-shifting module is shifted manually, whereas the main or top shifting modules are shifted automatically. Pneumatic shifting devices are designed for the main shifting module and the top shifting module and are activated when the gearshift path of the desired gear is selected through the respective manual shifting device. Thus, the shifting diagram corresponds with the shifting diagram of a regular six gear gearbox. The disadvantage of this gear design is, however, that separate pneumatic shifting devices have to be provided for in order to be able to shift the gears the way it is usually done in an H-shifting diagram.
Furthermore, we are familiar with a shifting device for motor vehicles from DE 30 00 577, in which a manual shift lever is shifted in an HH-shifting diagram. In this shifting device, two shift fingers are arranged on the selector shaft in such a way that only one shift finger each shifts the four gears of the basic transmission. When changing from the second into the third gearshift path, a pilot valve is actuated, which shifts the range. When shifting into the third and fourth path, the second shift finger is engaged. A disadvantage here is also the separate actuator mechanism of the transmission range.
DE 35 27 390 A1 also shows a manually shiftable, double clutch transmission in which one of the two clutches of the double clutch is engaged when the gearshift lever is actuated in one gearshift path. The disadvantage of this shifting device is that it is limited to only four forward gears when shifting purely manually without any additional power source.
Finally, a shifting device for a transmission is described in the unpublished DE 102 31 547 A1 in which at least one gearshift package is allocated to two non-successive gear transmission ratio steps of the transmission. This shifting device is equipped with a mechanical conversion device which enables the one manual contactor with an H-gearshift frame to shift such a transmission.
In this shifting device, the gearshift lever is guided in an H- or multiple-H-gearshift frame and coupled with gearshift shafts so that a movement of the gearshift lever in a gearshift path causes the gearshift shaft to swivel around its longitudinal axis. Furthermore, a gear wheel is mounted on the first gearshift shaft, which combines with a second gear wheel on a second gearshift shaft. When the first gearshift shaft rotates, the second gearshift shaft counter-rotates in the other direction. When selecting a gearshift path with the gearshift lever, the two gearshift shafts are forced to couple parallel to their longitudinal axis.
Furthermore, these two gearshift shafts have shift fingers which, depending on the gear the transmission was put in, interlock with gear-specific recesses in the sliding selector shafts who, in turn, are connected with gearshift forks. These gearshift forks again are connected with the sliding collars of the gearshift packages which, for the torsion-resistant connection of loose wheels with a gearshift shaft, are shifted axially on the respective gearshift shaft during a shifting actuation.
Even though this unpublished shifting device is associated with the advantage that, for example, a double clutch transmission with the described gear and gearshift package arrangement, while keeping almost all of its components, can also be used as manual gearbox and can be shifted with an H- or multiple-H-gearshifting gate, the design of the shifting device nevertheless turns out to be mechanically costly.
Therefore, the objective of the invention is to present a shifting device in the form familiar from DE 102 31 547 A1 which includes the advantages stated above, but which is less complex in its mechanical design.
The solution to this objective ensues from the characteristics of the main claim, while favorable further developments and designs of the invention can be taken from the sub-claims.